Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Brush both sides of the eggplant slices with olive oil and season with salt and pepper. Arrange them on the baking sheet in a single layer.
Bake the eggplant slices for 15-20 minutes, flipping halfway through, until they are tender and start to brown.
While the eggplant is baking, in a bowl, mix together almond flour, grated Parmesan cheese, Italian seasoning, and garlic powder.
Once the eggplant is done, remove from the oven and let it cool slightly. Reduce the oven temperature to 350°F (175°C).
In a separate bowl, beat the egg. Dip each eggplant slice into the egg, then into the almond flour mixture, coating both sides evenly.
Place the coated eggplant slices back onto the baking sheet and bake for another 10 minutes to form the crust.
Remove the crusts from the oven, spread each with a thin layer of marinara sauce, and sprinkle with shredded mozzarella cheese.
Return to the oven for an additional 5-10 minutes, or until the cheese is melted and bubbly.
Garnish with fresh basil leaves before serving.